Solar Terrestrial Activity Report

Last major update issued on June 13, 2012 at 04:50 UTC. Minor update posted at 17:05 UTC

[Solar and geomagnetic data - last month (updated daily)]
[Solar wind and electron fluence charts (updated daily)
[Solar cycles 21-24 (last update June 2, 2012)]
[Solar cycles 1-20]
[Graphical comparison of cycles 21, 22, 23 and 24 (last update June 2, 2012)]
[Graphical comparison of cycles 10, 12, 13, 14, 16 and 24 (last update June 2, 2012)]
[Historical solar and geomagnetic data charts 1954-2006 (last update April 5, 2007)]
[Archived reports since January 2003 (last update May 3, 2012)]

[POES auroral activity level since October 2009 - updated June 10, 2012]
[Solar polar fields vs solar cycles - updated June 27, 2011]

Recent activity

The geomagnetic field was quiet to major storm on June 12. Solar wind speed at SOHO ranged between 346 and 436 km/s.

Solar flux measured at 20h UTC on 2.8 GHz was 141.3 (increasing 10.4 over the last solar rotation). The Potsdam WDC planetary A index was 16 (STAR Ap - based on the mean of three hour interval ap indices: 16.1). Three hour interval K indices: 64211111 (planetary), 54101322 (Boulder).

The background x-ray flux is at the class B8 level.

At midnight UTC the visible solar disk had 10 spotted active regions (in 2K resolution SDO images).

Region 11494 [S16W87] was quiet and stable.
Region 11504 [S17E27] developed significantly and has polarity intermixing. M flares are possible.
Region 11505 [S10E27] developed slowly and was mostly quiet.
Region 11506 [N10E38] decayed significantly and was mostly quiet.
Region 11507 [S27E04] decayed slowly and appears to be maturing.

Spotted active regions not numbered or interpreted differently by NOAA/SWPC:
S1719 [S23E14] decayed slowly and quietly.
S1721 [N11E05] reemerged with a few tiny spots.
S1723 [S31W07] reemerged with a few spots.
S1726 [S15E12] was quiet and stable.
S1728 [N07W35] decayed slowly and quietly.

Minor update added at 17:05 UTC on June 13: AR 11504 produced a very long duration M1.2 event peaking at 13:17 UTC. This event was associated with a CME. STEREO imagery indicates that Earth may be just inside the path of the outer part of the CME core. The CME could will likely arrive late on June 15 or on June 16 and could cause unsettled to minor storm conditions, major storm intervals are possible.

Coronal mass ejections (CMEs)

June 10-11: No obviously Earth directed CMEs were observed in LASCO or STEREO imagery.
June 12: A filament eruption began slowly to the northwest of AR 11507 at 14h UTC and later on expanded to include filaments across most of the southern hemisphere. A CME was observed over the eastern limb in STEREO-A images starting at 17:54 UTC and over the west limb in STEREO-B images.

Coronal holes

Coronal hole history (since October 2002)
Compare today's report to the situation one solar rotation ago: 28 days ago 27 days ago 26 days ago

No obvious coronal holes are currently in or near potentially geoeffective positions. 

The above coronal hole map is based on a method where coronal holes are detected automatically. While the method may need some fine tuning, it has significant advantages over detecting coronal holes manually. The main improvement is the ability to detect coronal holes at and just beyond the solar limbs. Early results using this method for SDO images over a span of several weeks indicate a good match between coronal holes observed over the visible disk and their extent and position at the east and west limbs. Note that the polar coronal holes are easily detected using this method, the extent and intensity of both CHs are consistent with other data sources.

Propagation

Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is poor. Propagation on long distance northeast-southwest paths is poor.

Forecast

The geomagnetic field is expected to be quiet on June 13-14. The CME observed on June 12 could arrive during the latter half of June 15 and cause unsettled to active conditions.

1) Effects from a coronal hole could reach Earth within the next 5 days. When the high speed stream has arrived the color changes to green.
2) Effects from a CME are likely to be observed at Earth within 96 hours.
3) There is a possibility of either M or X class flares within the next 48 hours.

Green: 0-20% probability, Yellow: 20-60% probability, Red: 60-100% probability.

Active solar regions

Click on image for higher resolution image) Compare to the previous day's image

When available the active region map has a coronal hole polarity overlay where red (pink) is negative and blue (blue-green) is positive.

Data for all numbered solar regions according to the Solar Region Summary provided by NOAA/SWPC. Comments are my own, as is the STAR spot count (spots observed at or inside a few hours before midnight) and data for regions not numbered by SWPC or where SWPC has observed no spots. SWPC active region numbers in the table below and in the active region map above are the historic SWPC/USAF numbers.

Active region	Date numbered detected	Spot count			Location at midnight	Area	Classification		SDO / HMI 4K continuum image with magnetic polarity overlay		Comment
		SWPC	STAR SDO				SWPC	STAR	Current	Previous
			2K	1K
11494	2012.05.30 2012.05.31	1	1	1	S16W84	0050	HSX	HSX			area: 0160 location: S16W87
11498	2012.05.31 2012.06.01				N07W82						plage
11499	2012.06.01 2012.06.03	3			N15W71	0010	BXO				splotless
11502	2012.06.02 2012.06.04				S17W72						plage location: S16W65
S1709	2012.06.04				N13W54						plage
S1713	2012.06.06				N11W46						plage
11507	2012.06.07 2012.06.10	22	33	21	S27E02	0100	EAI	ESI			location: S27E04
11504	2012.06.08 2012.06.09	24	51	24	S17E28	0310	EKI	EHC			beta-gamma area: 0750
S1717	2012.06.08				S15W49						plage
S1718	2012.06.08				N34W55						plage
11505	2012.06.09	13	22	10	S09E24	0100	DAO	DAO			location: S10E27 area: 0220
S1719	2012.06.09		3	2	S23E14	0000		AXX
11506	2012.06.09 2012.06.10	9	16	6	N11E38	0100	HAX	CAO			area: 0170
S1721	2012.06.09		5		N11E05	0000		AXX
S1722	2012.06.09				S17W47						plage
S1723	2012.06.09		3		S31W07	0000		BXO
S1726	2012.06.10		4	1	S15E12	0000		BXO
S1727	2012.06.10				N10W32						plage
S1728	2012.06.10		1		N07W35	0000		AXX
Total spot count:		72	139	65
Sunspot number:		132	239	135	(total spot count + 10 * number of spotted regions)
Weighted penumbral SN:		102	169	95	(Sum of total spot count + classification weighting for each AR. Classification weighting: X=0, R=3, A/S=5, H/K=10)
Relative sunspot number (Wolf number):		79	84	74	k * (sunspot number). k = 0.6 for SWPC, k = 0.35 (changed from 0.45 on March 1, 2011) for STAR SDO 2K, k = 0.55 for STAR SDO 1K

Monthly solar cycle data

1) Running average based on the daily 20:00 UTC observed solar flux value at 2800 MHz.
2A) Current impact on the monthly sunspot number based on the Boulder (NOAA/SWPC) sunspot number (accumulated daily sunspots / month days). The official SIDC international sunspot number is typically 30-50% lower. 2B) Month average to date.
3) Running average based on the quicklook and definitive Potsdam WDC ap indices. Values in red are based on the definitive international Potsdam WDC ap indices.

This report has been prepared by Jan Alvestad. It is based on analysis of data from whatever sources are available at the time the report is prepared. All time references are to the UTC day. Comments and suggestions are always welcome.

SDO images are courtesy of NASA/SDO and the AIA, EVE, and HMI science teams.